The Ice Crystal Icing Hazard & Risk Mitigation:

Delta Air Lines’ Perspective

Bob Culver, Chief Line Check Pilot & Tom Fahey, Mgr. MeteorologyFriends/Partners Aviation Weather (FPAW)19 November 2015Las Vegas, NV

Ice Crystal Icing (ICI)

What is it?&

What can we do about it?

Airframe Icing Conditions

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Question:What Temperatures & Cloud Conditions produce Airframe Icing?

Answer:Temps Warmer than - 40C & Liquid Cloud droplets below freezing.

Typical Icing Requires Super-cooled Liquid Droplets• Liquid freezes on contact with cold wings & fuselage surfaces. • Ice crystals, regardless of size, do not adhere to a cold airframe

Source: NASA-Lewis/FAA/NCAR-RAP

Ice Crystal Icing (ICI) ConditionsMeteorology & Jet Engine Perspectives

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Question: What conditions produce Ice Crystal Icing (ICI)?

Short Answer: High Concentrations of Ice Crystals,

also called High Ice Water Content (HIWC)

Ice Crystals Build-up in Compressor

FAA has an Advisory Circular in effect for B787

• Portions of Engine Compressor are above freezing• Very small ice crystals are ingested into the engine

• Ice crystals partially melt & stick to warmer engine surfaces• Ice crystals melt as they impact the warm internal engine components • If, encounter persists, a thin film develops over parts of the engine • This enables further capture of ice crystals

• If prolonged Encounter: Engine Temperature is reduced < 0C:• Ice crystals begin to aggregate

Ice can block flow into engine core or shed into coreLeading to various engine malfunctions

(engine vibration, power loss or damage)

ICI Process in a Jet Engine

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What is the physical process producing ICI risk?

Core

Where have ICI incidents occurred?

6Source: “Weather Conditions Associated with Jet Engine Power Loss & Damage Due to Ingestion of Ice Particles: What we’ve Learned Through 2009” by Matthew L. Grzych & Jeanne G. Mason, The Boeing Company

• 67 events shown worldwide (some overlaid) by Boeing 1990’s-2009.• Well over 100 events have been identified.• The greatest # of events have occurred in Asia Inter-port area.

Ice Crystal Icing (ICI) AwarenessWeather & Operating Conditions

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Question:What weather/flying conditions produce most Ice Crystal Icing (ICI)?

Answer:• Deep convective systems over both ocean & land in a Tropical Airmass• ICI potential increases with denser convection & extended exposure. • Typically, at cruise level altitudes & in clouds, above strong convection

where little or no weather radar returns observed at flight altitude.

ICI Awareness Tools • Radar: Tactical ICI avoidance is a challenge because not easily identified on radar.• HIWC: Areas of High Ice Water Content (HIWC) are being estimated & provided

by some aviation weather vendors.

High Ice Water Content AwarenessA Tool & a Delta Meteorology Product

Enroute Product:

&Graphic

Tool: Risk Areas for ICI

• Last 1 Hr HIWC

• 2 Hrs previous

• 3 Hrs previous

Text

2 Delta Meteorology Products UsedPre-flight & En Route

TP CB19 051441Z1.CBA2.* ALERT *HAZ:TSTMS SOURCE:SATELLITEAREA:02N071W 00N068W

02N066W 04N070W CVRG:BKNTOPS:FL450TREND:NCMVG FROM:CELLS VRBLINFO: RISK ICE CRYSTALICING-B757 ACTION RQRD3.VALID 051441Z/060000Z4.CANCEL NONE

Example: TP MessagePreflight Depiction Product contains

• Forecast of tstrm coverage & area

Process• Dispatchers consider alternative

routes to avoid psbl ICI when: - BKN (>=50%) tstrm coverage fcsted & - Flt route through tstrm area is 100NM

or greater in distance.

En Route TP Product contains

• Report of current tstrm activityAdded Situational Awareness

• If High Ice Water Content (HIWC) area, 100nm or greater present:

“INFO” is added

Why the Attention?

An ICI Event • On 09 November 2014 a Delta B757-

200 operating from Japan to Mariana Islands experienced an engine irregularity & then diverted to Iwo Jima.

• Post event analysis determined that ice crystal icing was a factor in the engine shut down.

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A Boeing 757 Aircraft • Although ICI can occur on any aircraft

on any Delta fleet: • Fleets other than the B757 have engine

auto re-ignite / restart capability. • On B757 fleet “continuous ignition”

must be activated manually.

ICI Operating ProceduresNewly Developed

A Coordinated Effort Between:

Dispatch

Meteorology

Pilots

ICI Operating ProceduresNewly Developed

Multi Layered Approach

2. Tactical Avoidance

1. Strategic Avoidance

3. Mitigation if Encountered

ICI Operating ProceduresStrategic Avoidance

Pilot Preflight Planning example:at 00z for JFK-SJU Flight

TP CB36 102306Z1.BD2.* ALERT *HAZ:TROP STORMNAME:KATELAT/LON:32.5N072.7WTIME:POSN AT 10/2100ZMVG FROM:23026WIND:SFC 60G75KTTREND:NC…INFO:RISK ICE CRYSTAL

ICING-B757 ACTION RQRD

3.VALID 102306Z/110900Z4.CANCEL CB29

Upper Air Depiction: Issued at 19z Features Valid 06z TP - Issued & Valid 23zIncluded in preflight paperwork

Btwn JFK &

San Juan (SJU)Broken (BKN)

Tstrm coverage Fcsted

ICI Radar Operating ProceduresStrategic Avoidance

Pilot Preflight Planning example:NRT-GUM Flight

Only Scattered (SCT)

or less tstrm coverage forecast along route of flight

TP AI23 031837Z 1.GM 2.* ALERT * HAZ:TSTMS SOURCE:SATELLITE AREA:14N141E 11N146E

12N149E 17N145E CVRG:SCT TOPS:FL540 TREND:INC MVG FROM:CELLS 12015 INFO:RISK ICE CRYSTAL ICING-B757 ACTION RQRD

3.VALID 031837Z/040200Z 4.CANCEL AI07

Operating in ICI conditionsTactical Avoidance

Cockpit PreparationEn Route NRT- GUM

Cockpit

Text of TP

Operating in ICI conditionsTactical Avoidance

Radar Operation

Operating in ICI conditionsMitigation

MitigationWhen in IMC at or above xx,000’ and operating within an area identified by Boeing’s High Ice Water Content (HWIC) map:

ENGINE START SELECTORS ………………FLTIncreases engine flameout protection.

ENGINE ANTI-ICE Switches………………….ONIncreases engine stall margins

In-flight restarts after ICI event

Typically there is no engine damage after the ice has been ingested

and the engine may be restarted.

Question:Should an in-flight restart be considered?

Answer: Yes

Conclusions

ICI is manageable.

Meteorology, Dispatch, and Pilot teamwork & training are key.

The Ice Crystal Icing Hazard & Risk Mitigation:�Delta Air Lines’ PerspectiveSlide Number 2Airframe Icing ConditionsIce Crystal Icing (ICI) Conditions�Meteorology & Jet Engine PerspectivesICI Process in a Jet Engine  Where have ICI incidents occurred? Ice Crystal Icing (ICI) Awareness�Weather & Operating ConditionsHigh Ice Water Content Awareness�A Tool & a Delta Meteorology Product2 Delta Meteorology Products Used�Pre-flight & En RouteWhy the Attention?ICI Operating Procedures�Newly Developed ICI Operating Procedures�Newly Developed ICI Operating Procedures�Strategic Avoidance ICI Radar Operating Procedures�Strategic Avoidance Operating in ICI conditions�Tactical AvoidanceOperating in ICI conditions�Tactical AvoidanceOperating in ICI conditions�MitigationIn-flight restarts after ICI eventConclusions